10.17192/ziaf.2025.5.1.8791 Fleischhauer, Karen Karen Fleischhauer Co-Teaching in CLIL Teaching and learning among (non-)experts Zeitschrift für Interaktionsforschung in DaFZ : Vol 5 No 1 (2025) Philipps-Universität Marburg 2025 we-ness complementary co-teaching mathematics in situ interaction komplementäres Co-Teaching CLIL Wir-Gefühl In-situ-Interaktion CLIL Mathematik 2025-12-15 2025-12-15 de JournalArticle https://journals.uni-marburg.de/0009/2025/354/8791 urn:nbn:de:hebis:04-0009-2025-354-87916 https://doi.org/10.17192/ziaf.2025.5.1 https://journals.uni-marburg.de/0009/2025/354/8791/8791.png 2750-249X application/pdf The study explores co-teaching in the context of Content and Language Integrated Learning (CLIL), focusing in particular on collaboration between language and subject teachers in a university-level mathematics language course. It examines in situ interactions within co-teaching teams using qualitative content analysis of audio-recordings from non-participant classroom observations and complementary stimuated-recall interviews and analyses their multi-perspectivity and competence development. The study investigates how teams coordinate different areas of expertise and negotiate roles in cooperative teaching and learning situations. The analysis shows that co-teaching in this context fosters mutual learning, with teachers using each other as knowledge resources and developing approaches toward a shared teaching identity (‘we-ness’). The results suggest that interdisciplinary collaboration can help overcome rigid role divisions. 2750-249X Zeitschrift für Interaktionsforschung in DaFZ Vol 5 No 1 (2025)